This invention relates to apparatuses and techniques for forming and using fine particles.
It is known to fragment materials into small particles by vapor explosion. In vapor explosion, energy is applied to the interior of the material causing it to rapidly expand and form ultrafine particles in an explosion-like effect.
Early publications discussing vapor explosion are "Dynamics and Energetics of the Explosive Vaporization of Fog Droplets by a 10.6-UM Laser Pulse", by Peter Kafalas and Jan Harrman, APPLIED OPTICS, v. 12, n. 4, April 1973, pp. 772-775 and "Fog Droplet Vaporization and Fragmentation by a 10.6-UM Laser Pulse", by Peter Kafalas and A. P. Ferdinand, Jr., APPLIED OPTICS, v. 12, n. 1, Jan. 1983, pp. 29-33. Moreover, U.S. Pat. No. 4,620,098 describes the formation of ultrafine particles of several useful compounds using lasers and gas dispersion.
There are several known practical uses of apparatuses and processes that generate particles. One such use is in spray painting and another is for nebulizers in medicine. In prior art spray painting equipment, the particles are formed by high velocity gases or vibrators. The use of high velocity gas flows has the disadvantage of wasting substantial amounts of paint as a result of the aerodynamic flow around objects and the use of vibrators, such as piezoelectric crystals, has a disadvantage in that the piezoelectric crystals which have commonly been used with the high velocity gas flows create particles larger than desirable for some applications.